The present invention relates to ophthalmology, and more particularly to apparatus including a contact lens type construction which may be fitted on the eye including means for directing light thereinto so that a patient's peripheral vision extent can be measured.
In a typical eye examination, several tests may be conducted in order to determine the visual efficiency of a patient's eyes. One test often conducted is to determine the peripheral vision extent of the eyes. Typically, an ophthalmologist will move a point source of light from adjacent the side of a patient's head forwardly until the patient indicates that the light is seen. The light source used in such a test is, for example, an ophthalmoscope used by the doctor conducting the test.
A problem with the above-described peripheral vision test resides in the fact that the usual patient is aware that a point source of light will soon be within view, and therefore, the patient will tend to automatically shift the eyeball to view the light source. Of course, when such eyeball shifting occurs, the patient's peripheral vision extent is not being accurately measured. Some patients can be sufficiently trained to continuously maintain their eyes looking directly forwardly, but other patients simply cannot be so trained.
Another problem resulting from the use of a hand-held point source of light to determine peripheral vision resides in the fact that it is difficult to determine the exact location on the eye which responds to the light source.
With the above problems in mind, it is a general object of the present invention to provide an apparatus for accurately determining peripheral vision extent irrespective of shifting of the eye. More particularly, the present invention contemplates the use of a contact lens type construction to which are connected a plurality of optical fibers. The fibers are distributed over the area bounded by the periphery of the lens so as to extend through the lens at discrete locations thereon. The fibers may be selectively illuminated so that light will be directed into the eye. It can be appreciated that a patient's response to the illumination of a particular fiber would be independent of the positioning of the eye because the lens rides with the eye.
Another object of the present invention is to provide a simple and efficient light producing means for selectively illuminating each of the optical fibers. Additionally, it is desirable to selectively regulate the intensity of the light being directed into the eye.
These and additional objects and advantages of the present invention will be more readily understood from a consideration of the drawings and the detailed description of the invention.